This invention relates generally to a fusing apparatus employed in an electrostatographic printing machine, and more particularly concerns a sealing arrangement for an apparatus applying release material to a heated fuser member employed in the fusing apparatus.
In the process of electrostatographic printing, a latent image is recorded on a surface and rendered visible with particles. These particles are transferred to a sheet of support material, in image configuration. Thereafter, the particles are permanently affixed to a sheet of support material to form a copy of the orginal document. Electrostatographic printing includes both electrophotographic printing and electrographic printing. Electrophotographic printing employs a photoconductive member which is charged to a substantially uniform level to sensitize the surface thereof. A light image of an original document is projected onto the sensitized surface of the photoconductive member. This light image dissipates selectively the charge on the photoconductive member to record thereon an electrostatic latent image of the original document. Electrographic printing does not employ a photoconductive member or a light image to create a latent image of the original document. Generally, however, both of the foregoing processes utilize heat settable particles to develop the latent image. Afer the particles are transferred to a sheet of support material, heat is applied thereto so as to permanently affix the particles to the sheet of support material.
Various approaches have been devised for heating the particles on the sheet of support material to permanently fuse them thereto. For example, the sheet of support material with the particles thereon may pass through a pair of opposed rollers. In a system of this type, a heated fuser roller and a non-heated backup roller are employed. Preferably, the heated fuser roller has an outer surface covered with a polytetrafluoroethylene material, commonly referred to as Teflon, to which a release agent, such as silicone oil is employed. An alternate approach has been to utilize a bare metal heated roller which has a low molecular weight polyethylene applied thereto as a release agent. The release agent prevents the toner particles on the sheet of support material from adhering to the heated fuser roll. However, capillary action frequently causes migration of the release agent along the fuser roll longitudinal axis and leakage from the side marginal regions thereof.
Accordingly, it is a primary object of the present invention to improve the apparatus employed to apply release material to a fuser roll by preventing leakage of the release material along the fuser roll longitudinal axis.